Renewable fuse



1,687,246 J. H. HICKEY RENEWABLE FUSE Filed Aug. 5, 1926 //v VENTO/2. JH/v l/`/. H/CKEY.

l 1,687,246 PATENTA oFFlcE.

OHN H. HIC'KEY,' 0F SAN FRANCISCO; CALIFORNIA.

RENEWABLE FUSE.

Application led August 5, 1926. Serial No. 127,336.

My invention relates to improvements in fuses wherein a fusible conductor of predetermined current carrying capacity is ren-A vdered readily observable wit out removal from a fuse block, andv wherein renewal may be effected by replacing' an inner transparent shell only.

he primary object of my invention is to provide an improved fuse. Another object is to provide an improved f fuse wherein the fusible conductor is rendered readily observable without weakening the fuse housing and without endangering workmen in inserting or removing fuses.

A further object is to provide an improved device of the character described, wherein the fusible conductor is carried within an inner ller shell detachably enclosed within an outer covering, whereby the fuse may be renewed by vreplacing the inner shell only. 4'

Another object is to provide an improved v construction which will facilitate and permit an eihcient evacuation of the lfuse shell whereby the fuse may be operated in vacuum. f-

-A further object is to provide an improved construction which will facilitate the sealing of the conductor within the fuse.

3 0 A still further object is to provide` an improved construction which may be economically manufactured and which will effect.

a substantial saving inv renewal costs.

I accomplish these and other objects by Ineanscf the improved device disclosed in.

the drawings forming 'apart of the present application wherein like characters of reference are used to designate similar parts throughout-`the specificationv and drawings 40 andin which,

fuiig. 1l is a side elevation of my improved 2 is alongitudinal section of the fuse.

Fig." 3 is an end elevationcf the fuse, and.

Fig. ,4' isV a transverse sectiongtaken` upon the' line 4--4-of Fig.2`. 4 v

Referring to the drawings, my iinprove'd fuse will be seen to consist of a llershell 1Y formedv from glass or other suitable transarent material.' The shell 1 is tubular in orm and is rovided with annular shoulders 2 formed jacent the ends' thereo by indentin'g the shell inwardly, as best shown in Fig. 2 ofthe drawings.

Pans 3 having `laring'eclgesl are fitted the outer'sides of the shoulders 2.

Conductors 4 are carried `by the pans 3, said conductors having their inner 'ends extending axially inward to spaced relation within the shell 1. The outer ends of the conductors 4 extend outwardly through the pans 3 to points substantially flush with the ends of the shell. A fusible conductor 6 is secured between the spaced inner ends of the conductors 4, said conductor being designed to carry a predetermined current.

The outer ends of the conductors 4 are connected to contact plates 7 fitted Hush with the ends of the shell 1 and preferably having anoiiset center portion apertured to receive the ends of the conductors 4 and to permit said conductor ends to be soldered Iupon the outer surfaces o1 the plates. The

` space between the plates 7 and the ypans 3 at each end of the shell 1 is filled with a suitable cementiticus material 5, preferably litharge and' glycerine, adapted to effectively seal the plates7 and the conductors 4 within the ends of the shell l1. A tip 9 is formed within one of the indentations of the shellA 1, whereby the shell may be evacuated. The tip49 is formed at a point spaced at a considerable distance 4from the conductor, there- 'by permitting the tip to be heated for seal-I ingthe tube after the air is drawn out without affecting the fuse conductors.

A cover 11 is fitted around the shell 1 toA reinforce and strengthen the same and to prevent breakage of the shell when being inserted vor removed from a fuse block. The cover is cylindrical inl shape/and arranged to lit closely around the shell along the entire length thereof. The cover .is formed for any suitable non-conductive material and i' has openings 12 formed in the sides thereof at points opposite the fusibleconductor, whereby said conductor may be readily observed through the transparent shell.

'Caps 14 are fitted over the ends of the shell land cover 11. The caps' are made of conductive material and arranged to form contact with the contact blades` of a fuse bleek, the type illustrated in the drawing bemg provided withY contact blades' 16 of the orm commonly used in fuses designed to carry high power currents. The caps 14 are detachably secured by means of suitable securm prefers. ly bolts 17 having their heads. 18 soldered or otherwise, secured in connection with the lates 7- and arranged to extend outwardly't rough suitable openings formed in elements carried by the plates 7,

the caps, whereby suitable nuts 19 may be applied to detachably hold the caps in firm contact with the outersurfaces of the plates 7. The caps engage the plates 7 along a' sembled as'above described, is applied and4 operates in the usual manner, in so far as the conducting of electric current is concerned. The apertured cover combined with.'

the transparent shell l permits the' fuse to be observed without removingthe same from a fuse block. This ,is of material advantage, as a single glance will determine at once whether or not the'fuse lhas been blown and in this manner greatly 'facilitates the checkifng up of the fuses and the locating of blown uses.' v Y In the event a fuse is blown, my improved construction permits renewal by merely re-V placing the shell 1.- This is accomplished by oosenmg the nuts 19 and removing the caps 14.I The shell 1 may then be readily removed from the cover l1 and a-new shell inserted. The old caps are then replaced and the fuse is again ready for use. In practice, the shells are made in standard sizes to iit diierent sizes of fuse blocks and are designed to lit the covers and caps provided for the particular'sizeof fuse. The fillers may be. manufactured at a relatively lowtcost and by providing for the replacement .of -the filler shell alone a material saving is effected in renewal costs. Atthe same time, the covers-l1 insure a strength and ruggedne'ss suited to any ordinary- The provision of av glass filler shell sealed at the ends in the-manner above described is of importance also, because of the fact that the. shell may be readily evacuated.

When air is present within the fuse bodyl te fusible conductor becomes oxidiztld and t current carrying capacity is t lereby affected. By exhausting the air from the shell, this oxidization is avoided and the capacity of the conductor'ismaintained constant when in use. The evacuatingofthe fuse is also important, because'of` the fact that' it prevents a'sudden expansion of*l air, such as might otherwise burst the fuse shell.

' The tip 9 through which the air is exhausted is positioned within one of the indentations formed upon\ the' shell, thereby -obtaining suicient space between the tip and the conductor to prevent said conductor from becoming damaged by the heat applied in sealing the shell and also preventmg the possible breakage duexto expansion around the sealed end of theshell. The cement ap lied between the plates 7 and pans 3 afor an eicient sealing which may be 'easily arid `cheaply accomplished without the necessity the specific construction illustrated and described, but desire t'o avail myself of all modifications which may fall within the scope of the appended claims.

Having thus described my invention what I claim as n'ew vand desire to secure by Letters Patent is,

1. fuse comprising a shell; a fusible conductor mounted within the shell and extending longitudinally therethrough; contact plates mounted within the ends of the shell in connection .with the ends of the conductor; means for sealing the ends of the shell around the conductor and plates to permit theV shell to be evacuated adetachable cover enclosing the shell; 'and means for detachably retaining the cover upon the shell, said means being adapted to form electrical connection between the contact plates and a fuse block.

2. A fuse comprising a transparent shell; a fusible conductor mounted within the shell and extending longitudinally therethrough; contact plates mounted within the ends of the shell connection withrfthe'ends of the conductor; means for sealing the ends of the shell' around the conductor and plates to ermit the shell to be evacuated; a detac able cover enclosing the shell and hav- 3. A fuse comprising a transparent shell;-

a fusible conductor mounted within the shell and extending longitudinally therethrough: contact plates mounted within the ends of the shell in connection with the ends of the conductors; means for sealing the endsI ofv the shell around the ends of the conductor and the contact plates to permit the shell to be evacuated; a detachable cover enclosing the shell and having openings formed in the sides thereof, whereby the fusible conductor may be observed through the transpar'- ent shell; caps fitted over theendsA of the shell and cover, said caps being arranged to form electrical contact between the contact plates and a fuse block; and means carried .by 'the contact plates and engaging the caps for detachably retaining the caps and cover upon the shell.

4. In a renewable fuse,l a yfiller comprising a transparent shell; `annular shoulders -sealing lthe ends of the shell, whereby the same may -be evacuated.- 'f

risin a transparent shell; annular sho ders in ented into the shell adjacent the'ends thereof; plans fitted. against the oute sides of said s tendingr longitudinally through the shell and extending outwardl plates fitted within e ends ofthe shell and .connected to the endsof the conductor; and

set within the ends of the..

a cement fillin set within the ends of theoulders; a fusible conduc r exf through the pans;.V

shell between t e pans andthe lates to seal the ends of said shell, whereby e same may be evacuated; and an apertured cover detachably Y the fusible conductor may be observed, said cover being adapted to permit renewal of the fuse by replacing the filler onl f 6. In a renewable fuse, a w er comprising arent shell; annular shoulders indented into the shell adjacent the ends-there-Y of; pans fitted against the outer sides of said shoulders;conductors c onnected toeach pan and extending axially into spaced rela- -tion within the shell and having their outer ends extendin outwardly through'the pans; a .fusible con uctor ofY predetermined cu'rrent car inner en of the conductors; plates'iitted within the ends ofv theshell and connected to the ends of the conductors; and means for 7. -In a renewable fuse, a illercom a transparent shellgannular shoul ers 1n capacityA secured between theY secured around the shell, whereby .carrying capacity dented into the shell ad'acent the ends thereof; pans fitted against the outer sidesof said shoulders; conductors cnnectedto each 4pan land extendin within the tu e and having their outer ends extending. outwardl through the pans; a fusible conductor o predetermined current carrying' capacit secured between the inner ends of the con uctors; plates tted within theends of the shell and connected to the axially into spaced relation endsof the conductors; and means for sealingthe ends of the shell, whereby the same' may be evacuated; and an apertured cover detachably secured around the shell, whereby the fusible conductor ma be observed throu -h the transparent she said cover be-` ing a apted tdpermit th fuse by replacing the filler only.

8.In a renewable fuse, a filler comprising a 'transparent shell; annular shoulders' ine renewal of the dented into the shell adjacent the ends there` A of; pansA fitted against the outer sides of said shoulders; vconductors connected to each panaxially into spaced relationV and extendin the tu e and having their outer endsl extending outwardl through. the pans; a

fusible conductor o predetermined current secured between the inner ends of the con ctors; lates fitted within the ends of the shell an connected to the ends of the conductors; and means for sealing the ends-of the shell, whereb 'the same may be evacuated; an aperture V.cover detachably secured around the shell, whereby the fusible conductor may be observed' threugh the Atransparent shell; caps fitted over the ends of the cover' and shell and -a'rranged 'to formelectrical contact between the contact lates and a fuse block; and

means carri .by the contadt plates and detachably en the caps, whereby the fuse' l ma be renewed y replacing the hller only.

' s' witness whereof,lI hereby set my signature.

' JOI-INH. HICKEY. 

